Tesla unveils new generation of utility-scale batteries: Megapack 3 and Megablock
Source：pv magazine
Tesla has unveiled much-anticipated additions to its energy storage lineup, the Megapack 3 and Megablock – both designed to imrpove energy density, scalability and speed of deployment. The new products were unveiled during the RE+ renewable energy conference in Las Vegas.
Megapack 3 builds on the legacy of Tesla’s utility-scale storage products and represents a significant leap in energy density over its predecessors. It delivers approximately 5 MWh of storage capacity per unit, up from 3.9 MWh in the Megapack 2XL, which began shipping in 2022.
Megapack 3 integrates Tesla’s silicon carbide inverter and fire protection systems and incorporates battery cells sourced from the US, Southeast Asia, and China. A key design improvement is its simplified thermal bay, which reduces connection complexity by 78%.
Each Megapack 3 weighs around 39 tonnes and is engineered for global transportability on a standard seven-axle trailer, requiring no onsite assembly. Tesla plans to begin production of Megapack 3 at its upcoming Houston factory, which will have a planned annual capacity of 50 GWh.
The most significant innovation, however, comes in the form of Megablock – a pre-engineered, medium-voltage utility-scale solution that combines four Megapack 3 units with an integrated megavolt transformer and switchgear.
Each unit is designed to deliver 20 MWh AC of capacity, with a 25-year operational life and support for over 10,000 cycles. The system offers 91% round-trip efficiency at medium voltage, factoring in auxiliary loads, and is engineered to operate in extreme conditions – from -40°C to 60°C ambient temperatures.
According to Tesla, Megablock is optimized for rapid deployment and cost-efficiency, offering 23% faster installation and up to 40% lower construction costs compared to previous systems. With a site-level energy density of 248 MWh AC per acre, it allows high-capacity storage while maintaining all necessary clearances for installation and service access.
Tesla also emphasized Megablock’s modular design, which enables the deployment of up to 1 GWh of storage capacity in just 20 business days. This is courtesy of a new flexible busbar assembly which eliminates the need for above-ground cabling between the Megapacks and transformer, enabling a plug-and-play architecture that simplifies on-site work.
At the launch, Tesla emphasized its shift from maximizing container size to optimizing site-level efficiency, focusing instead on shipping constraints, transport logistics, and simplified deployment.
Deliveries of the new products will start in the second half of 2026, according to Tesla’s announcement on its X account.